数字时控器

题目要求：

1、　　在定时范围1分钟内，用开关设置两个任意时刻t1和t2，到t1时能够自动启动某一过程，t2时停止该过程.

2、　　定时精度1s

3、　　时间由数码管显示.

4、要求计数器具有异步清零功能，计数控制功能

-figures controller topics : 1, the scope of a regular minutes, Switching set two arbitrary time t1 and t2, t1 can be automatically activated when a particular process, t2 halt the process. 2, precision timing's a three-hour LED display. 4. Asynchronous requests counter is reset function, calculators control functions